1. Field of the Invention
The present invention relates to a mobile communication system, and more particularly, to a system and method of providing service to mobile terminals of a second generation (IS-95, IS-95B) and a third generation (IS-2000) using a CDMA Channel List and an extended CDMA Channel List.
2. Background of the Related Art
A base station in a mobile communication transmits a channel list to mobile station to carry out a mobile communication service. The channel list is allocated with a frequency of 1.28 MHz. In this case, the base station selects whether the allocated frequency allocation (FA) is used for the second generation (IS-95,IS-95A,IS-95B) mobile station service 2G or the third generation (IS-2000) 3G mobile station service.
The base station separately administers the FA to be used for 2G and 3G mobile station services in accordance with a recommendation of IS-2000. Generally, 1FA, 3FA, and 4FA are allocated for 2G mobile station service and 2FA is allocated fro 3G mobile station service. In this case, a bundle of FA to be used for 2G mobile station service is defined as a CDMA (code division multiple access) channel list, and a bundle of FA to be used for 3G mobile station service is defined as an Extended CDMA Channel List.
Therefore, a 2G terminal receives a CDMA Channel List and a 3G terminal receives a CDMA Channel List or Extended CDMA Channel List, thereby providing services such as the presently supported voice call, data call and the like.
FIG. 1 to FIG. 3 illustrate related art methods of carrying out mobile communication services. Referring to FIG. 1, a base station 10, which services 1FA, 2FA, and 3FA, allocates 1FA and 3FA to the CDMA Channel List for a 2G mobile terminal 11 in accordance with the IS-2000 recommendation. The base station 10 also allocates 2FA to the Extended CDMA Channel List for a 3G mobile terminal 12 to transmit. Therefore, the 2G mobile terminal 11 carries out services such as voice and data calls and the like by receiving the CDMA Channel List to which 1FA and 3FA are allocated. Similarly, the 3G mobile terminal 12 carries out services such as voice and data calls and the like by receiving the Extended CDMA Channel List to which 2FA is allocated.
Referring to FIG. 2, a base station 10, which services 1FA and 3FA only, allocates 1FA and 3FA to the CDMA Channel List in accordance with the IS-2000 recommendation. Thus no FA is allocated to the Extended CDMA Channel List. Therefore, the 2G mobile terminal 11 carries out services, such as voice and data calls, by receiving the CDMA Channel List to which 1FA and 3FA are allocated. The 3G mobile terminal 12, however, is unable to carry out services such as voice and data calls because no frequency is allocated to the Extended CDMA Channel List.
Referring to FIG. 3, a base station 10, which services 2FA only for the 3G mobile terminal 12, allocates 2FA to the Extended CDMA Channel List, but no FA to the CDMA Channel List. In this case, the 3G mobile terminal is able to carry out normal mobile station services, but the 2G mobile terminal, having no allocated FA to the CDMA Channel List, fails to perform any mobile station service.
In such a manner, the base station transmits the FA allocated to the CDMA Channel List and the Extended Channel List, whereby the 2G and 3G mobile terminals are able to provide subscribers with voice/data calls.
The related art mobile station service methods have various problems. For example, as shown in FIG. 2 and FIG. 3, 2G or 3G mobile station service cannot be carried out unless a FA for the 2G and 3G terminals is allocated thereto by the base station, even if there is a frequency available to provide a service.
Furthermore, a service provider is required to extend a new frequency for the 3G mobile mobile station service. When the 3G mobile terminals are not widely used, however, it is a waste of frequencies to expand the extra-FA for the 3G mobile terminals. Additionally, the 2G mobile terminals provide services through limited FA only, whereby services for random 2G terminals may be rejected.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.